EAC 24, LT 2085, September-October 1967
Page 30
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Transcription
was caused by observers being restricted to the lee side of the pilot house as frequently the windward side was taking heavy spray. This effectively limited the angle of observation; created a blind spot of 90-135 degrees, i.e., the horizon was cut by one-third. Also due to the fast, erratic, and severe motion of the vessel in even moderate seas the observer is not able to use field glasses extensively to scan the horizon. This greatly lessens his radius of visibility which in turn causes him to record fewer birds. Were heavy seas (10+ ft) encountered during a survey on these vessels, observations would have to be secured as all hatches are then secured as green water covers the pilot house. Even in more moderate seas if the vessel is headed directly into the sea the same "wet" conditions result. Over 826 miles and 82.8 hours of diurnal observation, 390 birds of 13 species* were recorded. One bird (a Shoveler) was collected. The low number of land birds recorded is thought to indicate lack of attraction to the small vessel. However it is possible this marks the end of their migration/dispersion movements. Synoptic highlights: 1) High numbers of migrating Sooty Shearwaters. 2) Increase in "Leach's" Storm Petrel numbers over last survey and their apparent southern migration. 3) Continued low number of phalaropes. 4) Only one land bird recorded. 5) Few marine mammals recorded. Black-footed Albatross 40 The number of albatross recorded on this cruise compares favor- ably with that of the last three cruises. This strongly suggests that albatross do follow small vessels as readily as they do larger vessels. (the previous three surveys were taken from a 400+ ft. vessel). There is no apparent explanation for the occurrence of the 14 recorded albatross in sector 4. On 34 of the total 40 albatross, rump color was recorded; the breakdown follows: Dark rumped 28 (82 %) White rumped 4 (12 %) Mottled rump 2 (6 %) *Albatross are not included in either of these totals.